class/System/System.Collections.Specialized/BitVector32.cs

   1 //
   2 // System.Collections.Specialized.BitVector32.cs
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Lawrence Pit (loz@cable.a2000.nl)
   7 //   Andrew Birkett (adb@tardis.ed.ac.uk)
   8 //   Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   9 //
  10 // (C) Ximian, Inc.  http://www.ximian.com
  11 // Copyright (C) 2005 Novell, Inc (http://www.novell.com)
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System.Text;
  34
  35 namespace System.Collections.Specialized {
  36
  37         public struct BitVector32 {
  38                 int bits;
  39
  40                 public struct Section {
  41                         private short mask;
  42                         private short offset;
  43
  44                         internal Section (short mask, short offset) {
  45                                 this.mask = mask;
  46                                 this.offset = offset;
  47                         }
  48
  49                         public short Mask {
  50                                 get { return mask; }
  51                         }
  52
  53                         public short Offset {
  54                                 get { return offset; }
  55                         }
  56 #if NET_2_0
  57                         public static bool operator == (Section v1, Section v2)
  58                         {
  59                                 return v1.mask == v2.mask &&
  60                                        v1.offset == v2.offset;
  61                         }
  62
  63                         public static bool operator != (Section v1, Section v2)
  64                         {
  65                                 return v1.mask != v2.mask ||
  66                                        v1.offset != v2.offset;
  67                         }
  68
  69                         public bool Equals (Section obj)
  70                         {
  71                                 return this.mask == obj.mask &&
  72                                        this.offset == obj.offset;
  73                         }
  74 #endif
  75                         public override bool Equals (object o)
  76                         {
  77                                 if (! (o is Section))
  78                                         return false;
  79
  80                                 Section section = (Section) o;
  81                                 return this.mask == section.mask &&
  82                                        this.offset == section.offset;
  83                         }
  84
  85                         public override int GetHashCode ()
  86                         {
  87                                 return mask << offset;
  88                         }
  89
  90                         public override string ToString ()
  91                         {
  92                                 return ToString (this);
  93                         }
  94
  95                         public static string ToString (Section value)
  96                         {
  97                                 StringBuilder b = new StringBuilder ();
  98                                 b.Append ("Section{0x");
  99                                 b.Append (Convert.ToString(value.Mask,16));
 100                                 b.Append (", 0x");
 101                                 b.Append (Convert.ToString(value.Offset,16));
 102                                 b.Append ("}");
 103
 104                                 return b.ToString ();
 105                         }
 106                 }
 107
 108                 // Constructors
 109
 110                 public BitVector32 (BitVector32 source)
 111                 {
 112                         bits = source.bits;
 113                 }
 114
 115                 public BitVector32 (int init)
 116                 {
 117                         bits = init;
 118                 }
 119
 120                 // Properties
 121
 122                 public int Data {
 123                         get { return bits; }
 124                 }
 125
 126                 public int this [BitVector32.Section section] {
 127                         get {
 128                                 return ((bits >> section.Offset) & section.Mask);
 129                         }
 130
 131                         set {
 132                                 if (value < 0)
 133                                         throw new ArgumentException ("Section can't hold negative values");
 134                                 if (value > section.Mask)
 135                                         throw new ArgumentException ("Value too large to fit in section");
 136                                 bits &= ~(section.Mask << section.Offset);
 137                                 bits |= (value << section.Offset);
 138                         }
 139                 }
 140
 141                 public bool this [int mask] {
 142                         get {
 143 #if NET_2_0
 144                                 return (bits & mask) == mask;
 145 #else
 146                                 long tmp = (uint)bits;
 147                                 return (tmp & (long)mask) == (long)mask;
 148 #endif
 149                         }
 150
 151                         set {
 152                                 if (value)
 153                                         bits |= mask;
 154                                 else
 155                                         bits &= ~mask;
 156                         }
 157                 }
 158
 159                 // Methods
 160
 161                 public static int CreateMask ()
 162                 {
 163                         return 1;
 164                 }
 165
 166                 public static int CreateMask (int prev)
 167                 {
 168                         if (prev == 0)
 169                                 return 1;
 170                         if (prev == Int32.MinValue)
 171                                 throw new InvalidOperationException ("all bits set");
 172                         return prev << 1;
 173                 }
 174
 175                 public static Section CreateSection (short maxValue)
 176                 {
 177                         return CreateSection (maxValue, new Section (0, 0));
 178                 }
 179
 180                 public static Section CreateSection (short maxValue, BitVector32.Section previous)
 181                 {
 182                         if (maxValue < 1)
 183                                 throw new ArgumentException ("maxValue");
 184
 185                         int bit = HighestSetBit(maxValue);
 186                         int mask = (1 << bit) - 1;
 187                         int offset = previous.Offset + HighestSetBit (previous.Mask);
 188
 189                         if (offset + bit > 32) {
 190                                 throw new ArgumentException ("Sections cannot exceed 32 bits in total");
 191                         }
 192
 193                         return new Section ((short) mask, (short) offset);
 194                 }
 195
 196                 public override bool Equals (object o)
 197                 {
 198                         return (o is BitVector32) && bits == ((BitVector32) o).bits;
 199                 }
 200
 201                 public override int GetHashCode ()
 202                 {
 203                         return bits.GetHashCode ();
 204                 }
 205
 206                 public override string ToString ()
 207                 {
 208                         return ToString (this);
 209                 }
 210
 211                 public static string ToString (BitVector32 value)
 212                 {
 213                         StringBuilder b = new StringBuilder ();
 214                         b.Append ("BitVector32{");
 215                         long mask = (long) 0x80000000;
 216                         while (mask > 0) {
 217                                 b.Append (((value.bits & mask) == 0) ? '0' : '1');
 218                                 mask >>= 1;
 219                         }
 220                         b.Append ('}');
 221                         return b.ToString ();
 222                 }
 223
 224                 // Private utilities
 225                 private static int HighestSetBit (int i)
 226                 {
 227                         int count = 0;
 228                         while(i >> count != 0)
 229                                 count++;
 230                         return count;
 231                 }
 232         }
 233 }